This application claims the priority of German Patent Document DE 101 59 090, filed Dec. 1, 2001, the disclosure of which is expressly incorporated by reference herein.
The invention is based on an oil catching device having an oil catching housing which is arranged below a crankcase and which has at least two oil collecting spaces, in a first oil collecting space, an oil pump being arranged which has two pump stages, at each of two suction stages, one oil suction pipe is connected; a first oil suction pipe reaching in the first oil collecting space in order to deliver lubricating oil by way of a delivery side of a first pump stage to consuming devices; and a second oil suction pipe connected with a second suction state leads to a second oil collecting space. The device also has an oil pump for an internal-combustion engine for suctioning off lubricating oil situated in an oil catching device, comprising an oil pump housing in which at least two pairs of gear wheels or two pairs of rotors are arranged, by rotation of which, at least two pump stages are formed each having a suction side and a delivery side.
In German Patent Document DE 100 14 368, an oil catching device is described as well as an oil pump arranged therein, in the case of which, by way of a double oil pump, the lubricating oil situated in the rearward collecting space is delivered into the actual oil sump of the internal-combustion engine before it is fed to the consuming devices by way of a second pressure or suction stage. Because air is also taken in from the rearward oil collecting space, an oil/air separator in the form of a swirl pot is arranged at the outlet of the second pressure stage, which swirl pot ensures that a large portion of the gas fractions are separated from the lubricating oil before the lubricating oil returns into the first oil collecting space or oil sump. This swirl pot requires additional space which is available only to a limited extent in the oil catching housing, and, in addition, it must be ensured that the oil outlet provided at the lower end of the oil/air separator is situated above the oil level formed in the oil sump.
An aspect of the invention is to provide devices by way of which the air taken in by the oil pump is separated before the lubricating oil is fed to the consuming devices. The devices for the air separation should be space-saving and be constructed such that the oil sump forming in the oil guiding housing does not impair the method of operation of the air separator.
This aspect can be achieved in that on a top side, a housing of the oil pump has an opening connected with a delivery side of a second pump stage, by way of which opening, oil suctioned out of the second oil collecting space is delivered into the first oil collecting space and in that an opening forming a pressure-side outlet leads into a through-shaped bordering shaped out of the oil pump housing.
Through the opening provided on the top side of the oil pump housing at the outlet of the second delivery side, the lubricating oil can flow out of the pressure space and, by way of the oil pump housing, flow off into the first oil collecting space. The lubricating oil has sufficient time for defoaming, so that the gas fraction of the lubricating oil is already considerably reduced when the latter flows into the oil sump.
In preferred embodiments, additional advantageous further developments and improvements are contained of the oil catching device or of the oil pump.
In order to lengthen the time for the self-defoaming of the lubricating oil, it is advantageously provided that the outlet opening situated on the top side of the oil pump housing is enclosed by a trough-type bordering, so that the lubricating oil emerging from the opening is caught in this type of trough until the excess lubricating oil flows off over the trough edge into the oil sump of the internal-combustion engine.
In the housing of the double oil pump, a pressure limiting valve is arranged and whose opening monitored by the valve body also discharges inside the trough-shaped bordering.
The double pump has two pump stages constructed as pairs of gear wheels, the first pump stage being provided for supplying the consuming devices, while the second pump stage returns the oil suctioned from the rearward oil connecting space into the forward oil collecting space.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.